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pokecrystal-board/docs/develop/index.md
xCrystal 5362006c4d Documentation
2023-10-28 21:22:30 +02:00

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Functions

Apply VRAM/OAM

  • SafeUpdateSprites: Set BG map mode to 0 (disabled) and disable OAM update + UpdateSprites + enable OAM update + DelayFrame + restore original state of BG map mode and OAM update
  • UpdateSprites: Compute state of overworld sprites to wShadowOAM. Disable OAM update while editing wShadowOAM, and restore its original state when finished
  • ApplyPals: Copy wBGPals1 into wBGPals2 and wOBPals1 into wOBPals2. Does not request pal update during vblank by itself
  • ApplyAttrmap: Set BG map mode to 2 (pals) and delay 4 frames, and finally restore original state BG map mode. If LCD disabled instead copy all pals at once immediately
  • ApplyTilemap: Set BG map mode to 1 (tiles) and delay 4 frames. If wSpriteUpdatesEnabled is non-0, instead call CopyTilemapAtOnce to do it all in one frame. This delays the next vblank to LY ~$7f

Load font

  • LoadFont_NoOAMUpdate: LoadFrame + Hide Window + LoadStandardFont with OAM update disabled
  • LoadOverworldFont_NoOAMUpdate: LoadOverworldFontAndFrame + hide Window with OAM update disabled

Textboxes

  • Textbox1bpp: TextboxBorder + TextboxAttributes1bpp
  • Textbox2bpp: _OverworldTextbox + TextboxAttributes2bpp
  • SpeechTextbox1bpp: Textbox1bpp with speech location and dimensions
  • SpeechTextbox2bpp: Textbox2bpp with speech location and dimensions
  • ClearTextbox: Clear the inside of a speech textbox (fill with " ")
  • PrintTextboxText: Print text in speech textbox coordinates with letter delay
  • PrintText1bpp, FarPrintText1bpp: SpeechTextbox1bpp + UpdateSprites + ApplyTilemap + ClearTextbox + PrintTextboxText
  • PrintText2bpp: SpeechTextbox2bpp + UpdateSprites + ApplyTilemap + ClearTextbox + PrintTextboxText
  • MapTextbox: ClearTextbox + redraw tile behind cursor + SafeUpdateSprites + disable OAM update + ApplyTilemap + PrintTextboxText + enable OAM update
  • MenuBox: Calls Textbox1bpp or Textbox2bpp, depending on the value of wText2bpp, with menu location and dimensions.

Overworld map scrolling

  • LoadScreenTilemap: From the metatile-based 24x20 map in wSurroundingTiles, load the corresponding 20x18 tiles to wTilemap. Later, BackupBGMap* from ScrollMap* copies new row/column from wTilemap to wBGMapBuffer. _ScrollBGMapPalettes populates wBGMapPalBuffer based on the tiles at wBGMapBuffer. These are read during vblank by UpdateBGMapBuffer.
  • LoadScreenAttrmapPals: Load wAttrmap palette numbers based on the tileset palettes of the current map. Called only by LoadScreenTilemapAndAttrmapPals.
  • LoadScreenTilemapAndAttrmapPals: LoadScreenTilemap + LoadScreenAttrmapPals. Often used to reload screen after closing a text box.

Overworld map anchoring

  • ReanchorBGMap_NoOAMUpdate: LoadScreenTilemapAndAttrmapPals + HDMATransferTilemapAndAttrmap_OpenAndCloseMenu, then fill BG map with all black while Window is displayed, finally anchor map and objects. Shall by followed by CopyTilemapAtOnce or by a HDMATransferTilemapAndAttrmap_* to redraw the screen.
  • OpenText1bpp, OpenText2bpp: ClearMenuAndWindowData + ReanchorBGMap_NoOAMUpdate + SpeechTextbox1bpp + HDMATransferTilemapAndAttrmap_OpenAndCloseMenu + hide Window
    • OpenText1bpp: Loads 1bpp font (LoadFont_NoOAMUpdate)
    • OpenText2bpp: Doesn't load 2bpp font
  • RefreshScreen: Same as OpenText functions but doesn't call any SpeechTextbox

VRAM transfer

  • Request1bpp, Request2bpp: Copy 1bpp or 2bpp tiles at a rate of TILES_PER_CYCLE (8) per frame during vblank. Wait until complete
  • Copy1bpp, Copy2bpp: Copy 1bpp or 2bpp tiles immediately
  • Get1bpp, Get2bpp: Call Copy1bpp or Copy2bpp if LCD disabled. Request1bpp or Request2bpp otherwise
  • HDMATransfer1bpp: Copy 1bpp tiles via HDMA. Maximum 16 tiles per frame
  • HDMATransfer2bpp: Copy 2bpp tiles via HDMA. No hardcoded limit. Timing considers 1 tile per hblank
  • Get1bppViaHDMA, Get2bppViaHDMA: Call Copy1bpp or Copy2bpp if LCD disabled. HDMATransfer1bpp or HDMATransfer2bpp otherwise
  • HDMATransferTilemapAndAttrmap_OpenAndCloseMenu, HDMATransferTilemapAndAttrmap_OverworldEffect: Similar, but with slightly different scanline timing. So they're essentially like RefreshScreen minus the anchoring part.

HUD

  • EnableWindowHUD: Configure LCD interrupt in LYC=LY mode with corresponding LYC.
  • DisableWindowHUD: Configure LCD interrupt in hblank mode
  • LoadHUD: Load the HUD at wWhichHUD to the top of wTilemap and wAttrmap
  • LoadWindowHUD: Like LoadHUD, but for HUDs that require a Window overlay. Only does anything if hWindowHUDLY is non-0
  • ConstructOverworldHUDTilemap: Draw the overworld HUD's tilemap into wOverworldHUDTiles
  • TransferOverworldHUDToBGMap: Transfer overworld HUD to vBGMap1/vBGMap3 during v/hblank(s). Tilemap is read from wOverworldHUDTiles, attrmap is all PAL_BG_TEXT | PRIORITY.
  • RefreshOverworldHUD: ConstructOverworldHUDTilemap + TransferOverworldHUDToBGMap

Scripts

  • refreshscreen: RefreshScreen
  • reloadmappart: LoadScreenTilemapAndAttrmapPals + GetMovementPermissions + HDMATransferTilemapAndAttrmap_OverworldEffect + UpdateSprites. Similar to refreshscreen, but does not reanchor. On the other hand, it refreshes movement permissions. Often used after a block change or field move, which can affect collisions.

Overworld loop (pokecrystal)

<f>Primary functions</f> are denoted in red and using indentation
<j>*[j<num>]*</j> means jumping ahead
<k>*r<num>_<ret_value>*</k> means break/return from current function with a return value
Horizontal line means end of loop
Bold denotes not documented yet
<c>This denotes a comment</c>

wMapStatus == MAPSTATUS_START:
$$wScriptRunning <= 0
$$wMapStatus ~ wMapStatusEnd <= 0

wMapStatus == MAPSTATUS_START or wMapStatus == MAPSTATUS_ENTER:
$$RunMapSetupScript
$$hMapEntryMethod == MAPSETUP_CONNECTION:
$~~~~~~~~$wScriptFlags2 <= $ff
$$hMapEntryMethod <= 0
$$wMapStatus <= MAPSTATUS_HANDLE

wMapStatus == MAPSTATUS_DONE:
$~~~~$Exit overworld loop

wMapStatus == MAPSTATUS_HANDLE: the remainder of the code goes at this level

hOverworldDelay <= 2 2 is MaxOverworldDelay
wMapEventStatus == MAPEVENTS_ON:
$$Get joypad update hJoyDown, hJoyReleased, hJoyPressed
$$Refresh pals

HandleCmdQueue runs cmds queued by callbacks of type MAPCALLBACK_CMDQUEUE that execute the writecmdqueue script. Used only for stone tables, where any boulder from that table that is on a pit tile is made to disappear.

MapEvents (wMapEventStatus == MAPEVENTS_ON):

PlayerEvents (wScriptRunning == FALSE): wScriptRunning check not to interrupt a running script command with wait/delay mode like applymovement and deactivatefacing

CheckTrainerBattle:
if seen by trainer (if any visible sprite is a trainer not yet beaten facing the player within line of sight):
$$update wSeenTrainerDistance, wSeenTrainerDirection, wSeenTrainerBank, hLastTalked
$$load trainer data to wTempTrainer ~ wTempTrainerEnd
$~~~~$[j1(PLAYEREVENT_SEENBYTRAINER)]

CheckTileEvent:
if warp, coord event, step event, or wild encounter:
$$[j1(PLAYEREVENT_CONNECTION / PLAYEREVENT_FALL / PLAYEREVENT_WARP / PLAYEREVENT_MAPSCRIPT / PLAYEREVENT_HATCH)] step events include: special phone call, repel, poison, happiness, egg, daycare, bike
$$may also CallScript(<coord_event_script> / Script_ReceivePhoneCall / RepelWoreOffScript / Script_MonFaintedToPoison / WildBattleScript / BugCatchingContestBattleScript)

RunMemScript:
if any script at wMapReentryScript: [j1] used for phone scripts

RunSceneScript:
if scene event (wCurMapSceneScriptCount): [j1(PLAYEREVENT_MAPSCRIPT)]

CheckTimeEvents:
if any time event: [j1] used for bug contest, daily events

OWPlayerInput:

PlayerMovement:

DoPlayerMovement:

wCurInput <= hJoyDown if BIKEFLAGS_DOWNHILL_F and hJoyDown & D_PAD == 0, instead load D_DOWN
wMovementAnimation <= movement_step_sleep
wWalkingIntoEdgeWarp <= FALSE

Tile collision checks below consist on reading the current tile wPlayerTile and comparing it to a COLL_ constant or a range of COLL_ constants.
Tile permission checks below consist on reading the permissions of the tile that the player is walking into: wTilePermissions (applies only to COLL_WALLs) and wWalkingTile (LAND_TILE, WATER_TILE, or WALL_TILE for the tile in the walking direction; WALL_TILE permission is not the same as a COLL_WALL collision).
wPlayerState == PLAYER_NORMAL or wPlayerState = PLAYER_BIKE:
$$if on ice tile and wPlayerTurningDirection != 0: wCurInput <= current direction button
$$update wWalkingDirection, wFacingDirection, wWalkingX, wWalkingY, wWalkingTile, based on wCurInput direction
$$if whirlpool tile: r1_player_movement = PLAYERMOVEMENT_FORCE_TURN
$$if waterfall tile: wWalkingDirection <= direction, DoStep(STEP_WALK), r1_player_movement = PLAYERMOVEMENT_CONTINUE
$$if door/staircase/cave warp tile (non ladder/carpet): wWalkingDirection <= DOWN, DoStep(STEP_WALK), r1_player_movement = PLAYERMOVEMENT_CONTINUE
$$if directions at wWalkingDirection and wPlayerDirection are not the same (turning): DoStep(STEP_TURN), r1_player_movement = PLAYERMOVEMENT_TURN
$$if no bump (land tile permissions or NPC): DoStep(STEP_WALK / STEP_BIKE / STEP_ICE)
$$if not leaving water: r1_player_movement = PLAYERMOVEMENT_FINISH
$$if leaving water: wPlayerState <= PLAYER_NORMAL, reload music and sprites, and r1_player_movement = PLAYERMOVEMENT_EXIT_WATER
$$if ledge tile: play sfx, DoStep(STEP_LEDGE), and r1_player_movement = PLAYERMOVEMENT_JUMP
$$if carpet warp tile matching wWalkingDirection: wWalkingIntoEdgeWarp <= TRUE
$~~~~~~~~$if directions at wWalkingDirection and wPlayerDirection are the same: load warp data, wPlayerTurningDirection <= 0, wMovementAnimation <= movement_step_sleep, and r1_player_movement = PLAYERMOVEMENT_WARP
$$wWalkingDirection == STANDING: wPlayerTurningDirection <= 0, wMovementAnimation <= movement_step_sleep
$~~~~$wWalkingDirection != STANDING: if wWalkingIntoEdgeWarp == FALSE, play bump sound, wPlayerTurningDirection <= 0, wMovementAnimation <= movement_step_bump

wPlayerState == PLAYER_SURF:
$$if on ice tile and wPlayerTurningDirection != 0: wCurInput <= current direction button
$$update wWalkingDirection, wFacingDirection: wWalkingX, wWalkingY, wWalkingTile, based on wCurInput direction
$$if whirlpool tile: r1_player_movement = PLAYERMOVEMENT_FORCE_TURN
$$if waterfall tile: wWalkingDirection <= direction, DoStep(STEP_WALK), r1_player_movement = PLAYERMOVEMENT_CONTINUE
$$if door/staircase/cave warp tile (non ladder/carpet): wWalkingDirection <= DOWN, DoStep(STEP_WALK), r1_player_movement = PLAYERMOVEMENT_CONTINUE
$$if directions at wWalkingDirection and wPlayerDirection are not the same (turning): DoStep(STEP_TURN), r1_player_movement = PLAYERMOVEMENT_TURN
$$if no bump (water tile permissions or NPC): DoStep(STEP_WALK / STEP_BIKE / STEP_ICE)
$$if not leaving water: r1_player_movement = PLAYERMOVEMENT_FINISH
$$if leaving water: wPlayerState <= PLAYER_NORMAL, reload music and sprites, and r1_player_movement = PLAYERMOVEMENT_EXIT_WATER
$$wWalkingDirection == STANDING: wPlayerTurningDirection <= 0, wMovementAnimation <= movement_step_sleep
$~~~~$wWalkingDirection != STANDING: if wWalkingIntoEdgeWarp == FALSE, play bump sound, wPlayerTurningDirection <= 0, wMovementAnimation <= movement_step_bump

wPlayerNextMovement <= wMovementAnimation
r1_player_movement = PLAYERMOVEMENT_NORMAL

r1_player_movement == PLAYERMOVEMENT_NORMAL or r1_player_movement == PLAYERMOVEMENT_JUMP or r1_player_movement == PLAYERMOVEMENT_FINISH: r2_player_event = 0
r1_player_movement == PLAYERMOVEMENT_WARP: r2_player_event = PLAYEREVENT_WARP
r1_player_movement == PLAYERMOVEMENT_TURN: r2_player_event = PLAYEREVENT_JOYCHANGEFACING
r1_player_movement == PLAYERMOVEMENT_FORCE_TURN: CallScript(Script_ForcedMovement), r2_player_event = PLAYEREVENT_MAPSCRIPT CallScript returns PLAYEREVENT_MAPSCRIPT always
r1_player_movement == PLAYERMOVEMENT_CONTINUE or r1_player_movement == PLAYERMOVEMENT_EXIT_WATER: r2_player_event = -1

r2_player_event == -1: r3_player_event = 0 in this case, apart from r2_player_event = -1, PlayerMovement has also returned nc
r2_player_event == 0: in this case, apart from r2_player_event = 0, PlayerMovement has also returned nc
$$if on ice tile and wPlayerTurningDirection != 0: [j2]
$$if A_BUTTON in hJoyPressed:
$$if facing to object event: CallScript(<object's script>) and r3_player_event = PLAYEREVENT_MAPSCRIPT / r3_player_event = PLAYEREVENT_ITEMBALL / load trainer data and r3_player_event = PLAYEREVENT_TALKTOTRAINER includes rock and boulder objects (PLAYEREVENT_MAPSCRIPT case)
$$if bg event (signpost) in current coords and facing, and event's flag set if any: CallScript(<event's script> / HiddenItemScript) and r3_player_event = PLAYEREVENT_MAPSCRIPT
$$if facing to collision event (use cut, whirlpool, waterfall, headbutt, surf): call TryXOW, which returns with CallScript(AskXOW / CantXOW) and thus r3_player_event = PLAYEREVENT_MAPSCRIPT
$~~~~$hJoyPressed[SELECT_F] == TRUE:
$$CallScript(SelectMenuScript) and r3_player_event = PLAYEREVENT_MAPSCRIPT
$~~~~$hJoyPressed[START_F] == TRUE:
$~~~~~~~~$CallScript(StartMenuScript) and r3_player_event = PLAYEREVENT_MAPSCRIPT
r3_player_event = r2_player_event in these instances is where PlayerMovement returned carry, so OWPlayerInput returns early

r3_player_event == 0: [j2]

[j1]
wScriptMode <= SCRIPT_READ
wScriptRunning <= loaded script from whatever jumped straight to [j1] OR r3_player_event

DoPlayerEvent (wScriptRunning == TRUE and wScriptRunning != PLAYEREVENT_MAPSCRIPT): if there is a non-PLAYEREVENT_MAPSCRIPT script requested during this loop iteration, DoPlayerEvent pushes it to make it be executed by ScriptEvents. So the code up to [j2] below here is actually executed by ScriptEvents and NOT right now.
All scripts below finish with the end script unless otherwise stated (e.g. by the endall script)

wScriptRunning == PLAYEREVENT_SEENBYTRAINER:
$~~~~$SeenByTrainerScript + StartBattleWithMapTrainerScript

wScriptRunning == PLAYEREVENT_TALKTOTRAINER:
$~~~~$TalkToTrainerScript + StartBattleWithMapTrainerScript

wScriptRunning == PLAYEREVENT_ITEMBALL:
$~~~~$FindItemInBallScript

wScriptRunning == PLAYEREVENT_CONNECTION:
$$hMapEntryMethod <= MAPSETUP_CONNECTION
$$wMapStatus <= MAPSTATUS_ENTER
$~~~~$wScriptFlags[SCRIPT_RUNNING] = FALSE

wScriptRunning == PLAYEREVENT_WARP:
$$play warp sound
$$hMapEntryMethod <= MAPSETUP_DOOR
$$wMapStatus <= MAPSTATUS_ENTER
$$wScriptFlags[SCRIPT_RUNNING] = FALSE this write is exactly what the 'end' script also does

wScriptRunning == PLAYEREVENT_FALL:
$$hMapEntryMethod <= MAPSETUP_FALL
$$wMapStatus <= MAPSTATUS_ENTER
$$wScriptFlags[SCRIPT_RUNNING] = FALSE
$$play fall sound 1
$$apply fall movement
$$play fall sound 2

wScriptRunning == PLAYEREVENT_WHITEOUT:
$~~~~$OverworldWhiteoutScript + Script_Whiteout ends with hMapEntryMethod <= MAPSETUP_WARP + wMapStatus <= MAPSTATUS_ENTER + endall

wScriptRunning == PLAYEREVENT_HATCH:
$~~~~$OverworldHatchEgg

wScriptRunning == PLAYEREVENT_JOYCHANGEFACING:
$$wScriptDelay <= 3
$$wScriptMode <= SCRIPT_WAIT
$$wScriptFlags[SCRIPT_RUNNING] = FALSE
$$wScriptFlags2[4] == TRUE enable wild encounters

[j2]
wScriptFlags2 <= 0

ScriptEvents: executes scripts requested this loop by CallScript (PLAYEREVENT_MAPSCRIPT)

wScriptFlags[SCRIPT_RUNNING] = TRUE
while wScriptFlags[SCRIPT_RUNNING] == TRUE: breaks after end or similar script command

$~~~~$wScriptMode == SCRIPT_OFF:
$~~~~~~~~$wScriptFlags[SCRIPT_RUNNING] = FALSE

$~~~~$wScriptMode == SCRIPT_READ:
$~~~~~~~~$(...)

$~~~~$wScriptMode == SCRIPT_WAIT_MOVEMENT:
$~~~~~~~~$(...)

$~~~~$wScriptMode == SCRIPT_WAIT:
$~~~~~~~~$(...)

wMapStatus != MAPSTATUS_HANDLE: [j3] jump if any script during this iteration changed wMapStatus (some warp ocurred)

HandleMapObjects:

HandleNPCStep Includes player object! At the beginning of each object, clears wPlayerStepVectorX, wPlayerStepVectorY, and wPlayerStepFlags, and sets wPlayerStepDirection to STANDING. HandleObjectStep is called for each visible object. This calls HandleStepType, which processes StepTypesJumptable by STEP_TYPE_. These functions manipulate wPlayerStepFlags among other things.

_HandlePlayerStep (wPlayerStepFlags != 0):

wPlayerStepFlags(PLAYERSTEP_START_F) == TRUE:
$$wHandlePlayerStep <= 4
$$Scroll map in the direction at wPlayerStepDirection
$$wHandlePlayerStep <= wHandlePlayerStep - 1 $$wPlayerBGMapOffsetX <= wPlayerBGMapOffsetX - wPlayerStepVectorX
$$wPlayerBGMapOffsetY <= wPlayerBGMapOffsetY - wPlayerStepVectorY
else wPlayerStepFlags(PLAYERSTEP_STOP_F) == TRUE:
$$Increase or decrease wYCoord or wXCoord according to wPlayerStepDirection
$$wHandlePlayerStep <= wHandlePlayerStep - 1
$$wHandlePlayerStep == 1: BufferScreen
$$wHandlePlayerStep == 0: GetMovementPermissions Update wPlayerTile, wTilePermissions, wTileDown, wTileUp, wTileLeft, and/or wTileRight
$$wPlayerBGMapOffsetX <= wPlayerBGMapOffsetX - wPlayerStepVectorX
$$wPlayerBGMapOffsetY <= wPlayerBGMapOffsetY - wPlayerStepVectorY
else wPlayerStepFlags(PLAYERSTEP_CONTINUE_F) == TRUE: same as PLAYERSTEP_STOP_F case except don't update wYCoord or wXCoord
$$wHandlePlayerStep <= wHandlePlayerStep - 1
$$wHandlePlayerStep == 1: BufferScreen
$$wHandlePlayerStep == 0: GetMovementPermissions Update wPlayerTile, wTilePermissions, wTileDown, wTileUp, wTileLeft, and/or wTileRight
$$wPlayerBGMapOffsetX <= wPlayerBGMapOffsetX - wPlayerStepVectorX
$$wPlayerBGMapOffsetY <= wPlayerBGMapOffsetY - wPlayerStepVectorY

CheckObjectEnteringVisibleRange (wPlayerStepFlags[PLAYERSTEP_STOP_F] == TRUE)

DelayFrames(hOverworldDelay)

HandleMapBackground UpdateActiveSprites + ScrollScreen

CheckPlayerState:
wPlayerStepFlags[PLAYERSTEP_CONTINUE_F] == FALSE:
$$wMapEventStatus <= MAPEVENTS_ON
wPlayerStepFlags[PLAYERSTEP_CONTINUE_F] == TRUE and (wPlayerStepFlags[PLAYERSTEP_STOP_F] == FALSE or wPlayerStepFlags[PLAYERSTEP_MIDAIR_F] == TRUE):
$$wMapEventStatus <= MAPEVENTS_OFF
else:
$$wScriptFlags2 <= $ff
$$wMapEventStatus <= MAPEVENTS_ON

[j3]

End of overworld loop. The remainder are intermediate functions

Every script executed by ScriptEvents finishes with the some form of the end command. It returns (by updating wScriptPos and wScriptBank) to a parent script if any, and otherwise:
wScriptRunning <= FALSE
wScriptMode <= SCRIPT_OFF
wScriptFlags[SCRIPT_RUNNING] = FALSE
The endall command is like end, but also finishes parent scripts regardless.

DoStep:

wWalkingDirection == STANDING:
$$wPlayerTurningDirection <= 0
$$wMovementAnimation <= movement_step_sleep
else:
$$wMovementAnimation <= <step (type, direction)>
$$wPlayerTurningDirection <= <direction> | 1 << 7
$~~~~$then always returns PLAYERMOVEMENT_FINISH but often is overwritten by caller

Board behavior

RAM addresses

  • hCurBoardEvent: holds a BOARDEVENT_ value.

  • wTurnData ~ wTurnDataEnd: not preserved on save, and cleared at the beginning of BoardMenuScript (i.e. on turn begin). It's part of wMapStatus ~ wMapStatusEnd, so it's also cleared by StartMap. Includes:

    • wDieRoll
    • wSpacesLeft

  • Addresses within wCurMapData ~ wCurMapDataEnd: preserved on save. Includes:

    • wCurTurn
    • wCurSpace
    • wCurSpaceStruct:
      • wCurSpaceXCoord
      • wCurSpaceYCoord
      • wCurSpaceEffect for non-branch spaces, or wCurSpaceBranchStructPtr (two bytes) for branch spaces
      • wCurSpaceNextSpace for non-branch spaces

  • These addresses share memory region with string buffers from wStringBuffer3 onwards.

  • wTempSpaceStruct: Temporary scope. Same structure as wCurSpaceStruct

  • wTempSpaceBranchStruct: Temporary scope. The structure is four bytes for next space for each direction (R/L/U/D; -1 if unavailable direction) followed by four bytes for required techniques for each direction (R/L/U/D)

Workflow

  1. OverworldLoop is called from GameMenu_WorldMap with either hMapEntryMethod = MAPSETUP_ENTERLEVEL or hMapEntryMethod = MAPSETUP_CONTINUE.
  2. StartMap resets wCurTurn and wCurSpace if MAPSETUP_ENTERLEVEL. StartMap sets hCurBoardEvent to BOARDEVENT_DISPLAY_MENU. wScriptFlags2 is cleared. wMapStatus is set to MAPSTATUS_HANDLE causing HandleMap to be called.
  3. MapEvents (from HandleMap) calls PlayerEvents. CheckBoardEvent queues BoardMenuScript which is executed by ScriptEvents.
  4. BoardMenuScript.Upkeep saves the game, clears wTurnData[], increases wCurTurn, and loads current space to wCurSpaceStruct[].
    • If player exits, the exitoverworld script sets wMapStatus to MAPSTATUS_DONE. This causes OverworldLoop to return back to the game menu. Exit this workflow.
  5. Player rolls die and the animation plays. After the animation, wDisplaySecondarySprites.SECONDARYSPRITES_SPACES_LEFT_F is set and hCurBoardEvent is set to BOARDEVENT_HANDLE_BOARD. At the end of this HandleMap iteration, CheckPlayerState sets wMapEventStatus to MAPEVENTS_ON (wScriptFlags2 is not touched so it remains cleared).
  6. In the next HandleMap iteration, CheckBoardEvent from PlayerEvents jumps to .board and then to .no_space_effect due to wScriptFlags2[4] not being set.
  7. Execution continues in PlayerEvents; OWPlayerInput is eventually called, and thus DoPlayerMovement. Here, StepTowardsNextSpace computes based on wCurSpaceNextSpace what direction key to write to wCurInput, causing the player to begin a movement in that direction.
  8. The player may need to turn to a different direction through the ChangeDirectionScript (when DoPlayerMovement returns with PLAYERMOVEMENT_TURN). Otherwise or after that, CheckPlayerState sets wMapEventStatus to MAPEVENTS_OFF,
  9. When the step finishes (i.e. PLAYERSTEP_STOP_F becomes set) in some HandleMap iteration, CheckPlayerState sets wScriptFlags2 to $ff and wMapEventStatus to MAPEVENTS_ON.
  10. In the next HandleMap iteration, CheckBoardEvent.board is called with wScriptFlags2[4] set.
    • If player is not above a tile (wPlayerTile) with a space collision: wScriptFlags2[4] is reset. Go back to 7.
    • If player is above a tile, the corresponding space script is queued to be executed by ScriptEvents in the current HandleMap iteration. wScriptFlags2[4] is reset. Continue to 11.
  11. The space script loads the value of wCurSpaceNextSpace into wCurSpace, and loads the new space data to wCurSpaceStruct[]. Unless the space is a Branch Space or a Union Space, wSpacesLeft is decreased.
    • If the space is a Branch Space, the branch data is loaded to wTempSpaceBranchStruct. Then the player is prompted to choose a valid direction. wCurSpaceNextSpace is populated with the next space that corresponds to the chosen direction. Go back to 6.
    • If the space is an End Space, a fading out animation plays and then the exitoverworld script sets wMapStatus to MAPSTATUS_DONE. This causes OverworldLoop to return back to the game menu. Exit this workflow.
  12. If wSpacesLeft is non-0, go back to 6.
  13. The script code specific to the space type of the landed-on space is executed.
    • If player whites out in battle, Script_BattleWhiteout executes exitoverworld. Exit this workflow.
  14. The landed-on space is disabled by executing a block change that converts it into a Grey Space. hCurBoardEvent is set to BOARDEVENT_END_TURN. CheckBoardEvent does nothing in this state. In the first subsequent HandleMap iteration where no other kind of event triggers causing PlayerEvents to return early, hCurBoardEvent is set to BOARDEVENT_DISPLAY_MENU.
  15. Go back to 3